Assembly For Covering a Trench

ABSTRACT

An assembly suitable for temporarily covering a trench comprises an anti-slip tile ( 30 ) and a separately formed trench cover. The anti-slip tile ( 30 ) may be releasably attached to the trench cover. The anti-slip tile ( 30 ) comprises a plurality of cylindrical protrusions ( 21 ) integrally formed with a body portion of the tile ( 30 ), protruding from an upper surface ( 6 ) of the body portion ( 5 ), and evenly spaced across the upper surface ( 6 ) to minimise the possibility of a wheel of a vehicle slipping as the wheel passes over the anti-slip tile ( 30 ) and over the trench cover. The body portion ( 5 ) has a plurality of openings ( 22 ) extending through the body portion ( 5 ), the openings ( 22 ) being spaced across the upper surface ( 6 ) to reduce the overall weight of the anti-slip tile ( 30 ), and to provide a means of draining rainwater from the upper surface of the body portion ( 5 ). Two openings ( 31   a ) are located at opposite end edges of the body portion ( 5 ). During assembly, a number of body portions ( 5 ) are placed on the surface of the trench cover and spaced at intervals to evenly cover the surface of the trench cover. A shaped, half round bracket is inserted into the matching opening ( 31   a ) in the surface of each body portion ( 5 ). The bracket can be fixed to the surface of the trench cover by means of a hardened nail fired from an impact gun.

INTRODUCTION

This invention relates to an assembly for temporarily covering a trench,for example a trench made in a footpath or a roadway.

It is known to use a large steel trench cover to temporarily cover atrench. Steel sheeting, which is typically manufactured in a foundryrolling process, is commonly used as the means of covering road openingsand trenches in order to allow traffic access while works are ongoing.However the use of this material presents a number of problems from asafety point of view, namely the difficulty of ensuring that the surfaceof the steel sheet has a sufficient Skid Resistance Value (SRV) whichwill protect vehicles from skidding under adverse or even normalroad/weather conditions. In particular slipping of a wheel of a vehicleas the wheel passes over such a trench cover, or slipping of a foot of apedestrian as they walk over such a trench cover frequently occurs. Thisslipping can cause traffic delays and/or lead to accidents occurring.

This invention is aimed at providing an assembly for covering a trenchwhich overcomes at least some of these problems.

STATEMENTS OF INVENTION

According to the invention there is provided an anti-slip element foruse with a separately formed trench cover, the anti-slip elementcomprising:

-   -   a body portion, the body portion being attachable to a        separately formed trench cover; and    -   means to minimise the possibility of another element slipping        upon passage of the other element over the body portion.

The anti-slip element minimises the possibility of a wheel of a vehicleslipping as it passes over the anti-slip element and over the trenchcover, or of a foot of a pedestrian slipping as they walk over theanti-slip element and over the trench cover. Thus the possibility oftraffic delays and/or accidents occurring is minimised.

By attaching the anti-slip element to the separately formed trenchcover, this enables the trench cover to be quickly and efficientlymanufactured in the most convenient manner, typically by rolling. Inparticular because the anti-slip element provides the means to minimisethe possibility of slipping, the trench cover may be manufactured withsmooth surfaces without the manufacturer needing to consider whethersuch smooth surfaces would present a potential slipping hazard.

If the manufacturer of the trench covers were to attempt to manufacturetrench covers integrally with some form of anti-slip means, this couldconsiderably complicate the manufacturing process. For example, tointegrally manufacture the trench cover with an anti-slip means maynecessitate machining the anti-slip means onto the surface of the trenchcover after rolling, or may necessitate a special die being used to formthe trench cover and integral anti-slip means. Complicating themanufacturing process in this manner could lead to a considerableincrease in the time and cost required to manufacture the trench cover.The extra time and cost required could cause particular problems in thecase where the trench cover is relatively large, for example a trenchcover having a length of 2.5 m and a width of 2 m.

In one embodiment of the invention the body portion is releasablyattachable to a trench cover.

Because the body portion can be detached from the trench cover, thisprovides the user with the freedom to re-use and/or re-position and/orrepair the anti-slip element, as desired.

The body portion may be attachable to a trench cover by means of amechanical attachment.

In one case the element comprises an attachment member extendablethrough the body portion and into a trench cover to attach the bodyportion to the trench cover. The attachment member may comprise a headpart for engaging the body portion, and a leg part extendable throughthe body portion and into a trench cover. The head part may bedetachable from the leg part to facilitate release of the attachment ofthe body portion to a trench cover. In one case the attachment member isconfigured to be driven into a trench cover by an impact gun. The bodyportion may comprise an access opening therethrough, through which theattachment member is extendable.

In another embodiment the body portion comprises a main body partcomprising a main opening, and a filler part locatable in the mainopening to at least partially fill the main opening. The filler part maycomprise the access opening therethrough. In one case the body portioncomprises a lower surface for contacting a trench cover when the bodyportion is attached to the trench cover, and the main opening at leastpartially tapers inwardly towards the lower surface. The filler part maybe at least partially tapered. The filler part may be at least partiallysubstantially wedge shaped. In one case the main opening is located atan edge of the main body part. In cross-section perpendicular to thelongitudinal axis of the main opening, the main opening may besubstantially “C”-shaped. In cross-section perpendicular to thelongitudinal axis of the filler part, the filler part may besubstantially “C”-shaped. In cross-section perpendicular to thelongitudinal axis of the main opening, the main opening may have an atleast partially, substantially half-round shape. In cross-sectionperpendicular to the longitudinal axis of the filler part, the fillerpart may have an at least partially, substantially half-round shape.

In another case the main opening is located substantially in the regionof the centre of the main body part. In cross-section perpendicular tothe longitudinal axis of the main opening, the main opening may have anat least partially non-round shape. In cross-section perpendicular tothe longitudinal axis of the filter part, the filter part may have an atleast partially non-round shape.

In a further embodiment of the invention the element comprises anattachment member for clamping the body portion to a trench cover. Theattachment member may comprise a lip for extending over at least part ofthe body portion to clamp the body portion to a trench cover. Theattachment member may comprise a first wing configured to be fixed to atrench cover. The element may comprise a fixing member drivable throughthe first wing to fix the first wing to a trench cover. The fixingmember may be configured to be driven through the first wing by animpact gun. In one case the body portion comprises a fixing opening, thefirst wing being locatable in the fixing opening. The attachment membermay comprise a second wing configured to be located between the bodyportion and a trench cover. The body portion may comprise a recess foraccommodating the second wing.

A single attachment member may be configured to clamp the body portionsof two or more elements to a trench cover.

In certain cases, a user may clamp two or more anti-slip elements to asingle trench cover using a single attachment member. This mayconsiderably reduce the time and labour required to cover a trench whileensuring a non-slip environment.

In a further case the body portion is attachable to a trench cover bymeans of welding.

The slip minimisation means may be integrally formed with the bodyportion.

In one embodiment the body portion comprises an upper surface for facingaway from a trench cover when the body portion is attached to the trenchcover, and the slip minimisation means comprises one or more protrusionsprotruding from the upper surface. The slip minimisation means maycomprise a plurality of protrusions evenly spaced across the uppersurface. Each of the protrusions may be substantially identical. Theslip minimisation means may comprise one or more first protrusions andone or more second protrusions, the one or more first protrusionsprotruding a greater distance from the upper surface than the one ormore second protrusions. The first protrusion may protrude approximately4 mm from the upper surface. The second protrusion may protrudeapproximately 2 mm from the upper surface. In one case the slipminimisation means comprises a plurality of first protrusions and aplurality of second protrusions, the first protrusions being at leastpartially arranged in a substantially “W”-shaped pattern relative to thesecond protrusions.

The “W”-shaped pattern of the protrusions on the anti-slip element hasbeen found in certain cases to be especially effective. In particular ithas been found that this pattern causes the wheel of a vehicle toinitially contact one of the lower protrusions as the wheel rolls ontothe anti-slip element, and then snag on one of the higher protrusionsregardless of the direction of approach of the vehicle.

In another embodiment the body portion comprises one or moreweight-reducing discontinuities. The discontinuity may comprise anopening extending through the body portion.

The openings through the anti-slip element contribute to reducing theoverall weight of the anti-slip element. Thus the anti-slip elementeffects the function of reducing the possibility of slippage occurring,while remaining easy to handle and transport.

In a further embodiment the body portion comprises drainage means. Thedrainage means may comprise an opening extending through the bodyportion.

The openings provide a means of draining water, such as rainwater, froman upper surface of the body portion. By draining away surface water,the overall anti-slip properties of the tile are improved.

The thickness of the body portion may be between 25 mm and 30 mm.

In another aspect of the invention, there is provided an assembly forcovering a trench, the assembly comprising: —

-   -   an anti-slip element of the invention; and    -   a separately formed trench cover.

In one embodiment of the invention the trench cover comprises a metallicmaterial, and/or a composite material. The metallic material maycomprise steel.

The trench cover may be manufactured by rolling, or drawing, orextruding, or casting, or injection moulding.

In one case the length of the trench cover is greater than 2 m. Thewidth of the trench cover may be greater than 0.3 m. The surface area ofthe trench cover may be greater than 1 m². The mass of the trench covermay be greater than 5 kg.

In another embodiment the trench cover comprises an upper surface, andthe upper surface is substantially smooth.

The trench cover may be configured to extend over a trench to cover thetrench as a substantially continuous cover.

In a further aspect, the invention provides a method for covering atrench, the method comprising the steps of: —

-   -   providing an anti-slip element;

providing a separately formed trench cover;

attaching the anti-slip element to the trench cover; and

positioning the trench cover with respect to the trench to cover thetrench.

In one case the anti-slip element is attached to the trench cover beforecovering the trench. In another case the anti-slip element is attachedto the trench cover while the trench cover is in position covering thetrench.

In one embodiment the anti-slip element is attached to the trench coverby extending an attachment member through the anti-slip element and intothe trench cover. An impact gun may be used to drive the attachmentmember into the trench cover.

The anti-slip element may be clamped to the trench. In one case a partof an attachment member is extended over at least part of the anti-slipelement to clamp the anti-slip element to the trench cover. The methodmay comprise the step of fixing the attachment member to the trenchcover. Two or more anti-slip elements may be attached to the trenchcover using a single attachment member.

In one case the anti-slip element is releasably attached to the trenchcover. The method may comprise the steps of releasing the attachment ofthe anti-slip element to the trench cover, and removing the anti-slipelement. The attachment of the anti-slip element to the trench cover maybe released by detaching a head part of an attachment member from a legpart of the attachment member.

In another aspect the invention provides an anti-slip assemblycomprising: —

-   -   a plate having one or more recesses in a surface of the plate;        and    -   one or more corresponding stud elements for location in the one        or more recesses to protrude from the surface of the plate.

The plate may comprise a trench cover.

In a further aspect, the invention provides a trench cover comprising:

-   -   a cover member for extending over a trench;    -   the cover member comprising a pair of supporting portions        bridged by a central trench covering portion; and    -   a cushioning member for cushioning the cover member relative to        the ground on at least one side of the trench.

The cushioning member acts to minimise vibration of the cover memberwith respect to the ground, even when the surface of the ground at theside of the trench is uneven. The cushioning member also assists inminimising any noise generated as traffic and pedestrians pass over thetrench cover.

In one embodiment of the invention the cushioning member is configuredto cushion the cover member relative to the ground on both sides of thetrench.

The cushioning member may comprise two or more separate cushioningelements.

In one case the cushioning member is configured to be located between atleast part of the supporting portion and the ground on a side of atrench. The cushioning member may be mounted to the supporting portion.The cushioning member may be mounted to the lower surface of thesupporting portion. In one case the cushioning member is mounted to thesupporting portion by means of engagement of a male protrusion in afemale recess. The cushioning member may comprise the male protrusionand the supporting portion may comprise the female recess.

The cushioning member may be of a resilient material, such as rubber.

In one embodiment at least part of the cushioning member protrudesdownwardly from a lower surface of the cover member.

The cover may comprise means to minimise the possibility of an elementslipping upon passage of the element over the cover member.

The invention also provides in a further aspect a trench covercomprising:

-   -   a cover member for extending over a trench;    -   the cover member comprising a pair of supporting portions        bridged by a central trench covering portion; and    -   means to minimise the possibility of an element slipping upon        passage of the element over the cover member.

In one embodiment of the invention the slip minimisation means isintegrally formed with the cover member.

The cover member may comprise an upper surface for facing away from atrench when the cover member is extended over the trench, and the slipminimisation means comprises one or more protrusions protruding from theupper surface. The slip minimisation means may comprise a plurality ofprotrusions evenly spaced across the upper surface. Each of theprotrusions may be substantially identical.

In one case in a first cross-section perpendicular to the longitudinalaxis of the protrusion, the protrusion has a substantially round shape.In a second cross-section perpendicular to the longitudinal axis of theprotrusion, the protrusion may have a substantially square shape. Theupper portion of the protrusion may have the substantially square shapeand the lower portion of the protrusion may have the substantially roundshape.

In one embodiment of the invention the cover comprises a trench elementdepending from the cover member to confine the cover member with respectto a trench. The trench element may be movable relative to the covermember to facilitate adjustment to a desired width of trench.

Because both of the trench engaging elements are movable relative to thecover member, this enables the cover to be adjusted to suit the width ofthe trench, while ensuring the cover may be positioned centrally overthe trench with substantially equal amounts of the supporting portionson each side of the trench.

A single relatively compact cover may be adjusted to cover a large rangeof trenches of different widths in a simple, efficient manner.

Also in one case because the trench engaging elements are movablelongitudinally rather than rotatably movable, the orientation of thetrench engaging elements may be predetermined for any width of trench.Thus, a uniform predictable performance is achieved.

The handle portion enables a user to easily and quickly grip the trenchengaging element to move the trench engaging element to a desiredposition.

In one case the cover comprises interlink means comprising a firstinterlink means at one transverse side of the cover member and acomplementary second interlink means at an opposite transverse side ofthe cover member, one of the first or second interlink means beingengagable underneath the other of the first and second interlink meansof a like cover on assembly.

The invention further provides an assembly for covering a trench, theassembly comprising a plurality of trench covers of the invention.

The invention enjoys a number of advantages in comparison to alternativeanti-skid systems. For example if it were attempted to provide asatisfactory anti-skid surface, with a particular SRV, by applying to atrench cover a combination of epoxy resin which has been impregnatedwith a specific type of abrasive grit, this method would be laboriousand costly to apply and would typically have a life-span of only 6 to 18months in urban areas with average traffic flows. It would then benecessary to transport the steel plate to a specialist facility eachtime for processing. It would also be necessary to constantly monitorthe system while on site in order to maintain the required SRV.

According to the invention there is provided a method whereby aspecially designed and manufactured anti-skid tile is used to providethe required SRV at reduced cost and greatly extended life.

The tile of the invention has an effective mechanical means of fixing tothe surface of the steel road plate and can be removed and replaced asindividual units when repairs are required.

The tile, which can be cast, formed, or moulded, has a set ofprotrusions on the upper surface which have been specifically designedand spaced in such a way as to provide the required skid resistancevalue. On a typical steel sheet of given dimensions, a full set of tilescan be placed and spaced in such a way as to completely cover thesurface of the road plate.

The mechanical fixing method may comprise in one embodiment a locationbracket, which would be positioned within recesses in the tile and whichwould therefore hold the tile in situ.

It is possible to fix the location bracket in position by a variety ofmeans, such as welding or by the firing of a hardened steel naildirectly through the location bracket and into the surface of the steelroad plate, thus holding the tile in a given position.

The bracket may be removed at any stage, by means of abrasive grinding,if repair or replacement is necessary.

The tile may be manufactured with integral holes between the anti-skidprotrusions, as these holes act as a means to facilitate the drainage ofwater from the surface of the tile in order to maintain the SRV in wetconditions.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will be more clearly understood from the followingdescription of some embodiments thereof, given by way of example only,with reference to the accompanying drawings, in which: —

FIG. 1 is a perspective view of an assembly for covering a trenchaccording to the invention;

FIG. 2 is a side view of the assembly of FIG. 1;

FIG. 3 is a plan view of an anti-slip element of the assembly of FIG. 1;

FIG. 4 is a view along line IV-IV in FIG. 3;

FIG. 5 is a view along line V-V in FIG. 3;

FIG. 6 is a perspective view of the assembly of FIG. 1, in use;

FIG. 7 is a side view of the assembly of FIG. 1, in use.

FIG. 8 is a plan view from above of an anti-slip element of anotherassembly for covering a trench according to the invention;

FIG. 9 is a plan view from below of the element of FIG. 8;

FIG. 10 is an end view of the element of FIG. 8;

FIG. 11 is an elevation view of the element of FIG. 8;

FIG. 12 is a view along line XII-XII in FIG. 8;

FIG. 13 is an enlarged, cross-sectional, end view of the element of FIG.12;

FIG. 14 is a perspective view of a main body part and two filler partsof the element of FIG. 8;

FIG. 15 is a plan view of one of the filler parts of FIG. 14;

FIG. 16 is an elevation view of the filler part of FIG. 15;

FIG. 17 is a view along line D-D in FIG. 15;

FIG. 18 is a plan view of the filler part of FIG. 15 and the main bodypart of FIG. 14;

FIG. 19 is a view along line XIX-XIX in FIG. 18;

FIG. 20 is a perspective view of a main body part of an anti-slipelement of another assembly for covering a trench according to theinvention;

FIG. 21 is a plan view from above of a filler part of the element ofFIG. 20;

FIG. 22 is an elevation view of the filler part of FIG. 21;

FIG. 23 is an end view of the filler part of FIG. 21;

FIG. 24 is a plan view from below of the filler part of FIG. 21;

FIG. 25 is another end view of the filler part of FIG. 21;

FIG. 26 is a view along line XXVI-XXVI in FIG. 21;

FIG. 27 is a view along line XXVII-XXVII in FIG. 21;

FIG. 28 is a perspective view from above of the filler part of FIG. 21;

FIG. 29 is a perspective view from below of the filler part of FIG. 21;

FIG. 30 is a plan view from above of a body portion of an anti-slipelement of another assembly for covering a trench according to theinvention;

FIG. 31 is a plan view from below of the body portion of FIG. 30;

FIG. 32 is an elevation view of the body portion of FIG. 30;

FIG. 33 is a view along line XXXIII-XXXIII in FIG. 30;

FIG. 34 is a perspective view from above of the body portion of FIG. 30;

FIG. 35 is a perspective view from below of the body portion of FIG. 30;

FIG. 36 is a plan view from above of an attachment member of the elementof FIG. 30;

FIG. 37 is an elevation view of the attachment member of FIG. 36;

FIG. 38 is a perspective view from below of the attachment member ofFIG. 36;

FIG. 39 is a perspective view from above of the attachment member ofFIG. 36;

FIG. 40 is a plan view of a body portion of an anti-slip element ofanother assembly for covering a trench according to the invention;

FIG. 41 is a plan view of an attachment member of the element of FIG.40;

FIG. 42 is an end view of the attachment member of FIG. 41;

FIG. 43 is a plan view of the attachment member of FIG. 41 and the bodyportion of FIG. 40, in use;

FIG. 44 is an enlarged, plan view of the attachment member of FIG. 43and the body portion of FIG. 43;

FIG. 45 is a perspective view from above of a trench cover according tothe invention;

FIG. 46 is a perspective view from below of the trench cover of FIG. 45;

FIG. 47 is a plan view from above of a cover member of the trench coverof FIG. 45;

FIG. 48 is a plan view from below of the cover member of FIG. 47;

FIG. 49 is an elevation view of the cover member of FIG. 47;

FIG. 50 is a perspective view from above of the cover member of FIG. 47;

FIG. 51 is a perspective view from below of the cover member of FIG. 47;

FIG. 52 is another perspective view from above of the cover member ofFIG. 47;

FIG. 53 is an enlarged, plan view from above of the cover member of FIG.47;

FIG. 54 is another enlarged, plan view from above of the cover member ofFIG. 47;

FIG. 55 is a plan view from below of a trench element of the trenchcover of FIG. 45;

FIG. 56 is a plan view from above of the trench element of FIG. 55;

FIG. 57 is an elevation view of the trench element of FIG. 55;

FIG. 58 is another elevation view of the trench element of FIG. 55;

FIG. 59 is an end view of the trench element of FIG. 55;

FIG. 60 is another end view of the trench element of FIG. 55;

FIG. 61 is a perspective view from below of the trench element of FIG.55;

FIG. 62 is a perspective view from above of the trench element of FIG.55;

FIG. 63 is a plan view from below of a cushioning member of the trenchcover of FIG. 45;

FIG. 64 is a plan view from above of the cushioning member of FIG. 63;

FIG. 65 is an elevation view of the cushioning member of FIG. 63;

FIG. 66 is another elevation view of the cushioning member of FIG. 63;

FIG. 67 is an end view of the cushioning member of FIG. 63;

FIG. 68 is another end view of the cushioning member of FIG. 63;

FIG. 69 is a view along line Z-Z in FIG. 64;

FIG. 70 is a view along line Y-Y in FIG. 64;

FIG. 71 is a view along line X-X in FIG. 64;

FIG. 72 is a perspective view from below of the cushioning member ofFIG. 63;

FIG. 73 is a perspective view from above of the cushioning member ofFIG. 63;

FIG. 74 is a plan view from above of another cushioning member of thetrench cover of FIG. 45;

FIG. 75 is a plan view from below of the cushioning member of FIG. 74;

FIG. 76 is an elevation view of the cushioning member of FIG. 74;

FIG. 77 is a view along line W-W in FIG. 76;

FIG. 78 is a perspective view from above of the cushioning member ofFIG. 74; and

FIG. 79 is a perspective view from below of the cushioning member ofFIG. 74.

DETAILED DESCRIPTION

Referring to the drawings, and initially to FIGS. 1 to 7 thereof, thereis illustrated an assembly 1 suitable for temporarily covering a trench2. The assembly 1 comprises an anti-slip tile 4 and a separately formedtrench cover 3. The anti-slip tile 4 may be releasably attached to thetrench cover 3 to minimise the possibility of, for example, a wheel of avehicle slipping as the wheel passes over the tile 4 and over the trenchcover 3.

The trench cover 3 is manufactured from steel in this case, preferablyby rolling the steel into the shape of the trench cover 3 as illustratedin FIG. 1. In this case, the trench cover 3 has a width W ofapproximately 1.2 m and a length L of approximately 2.5 m, and has amass of approximately 1000 kg.

The upper surface of the trench cover 3 is substantially smooth. Whenthe trench cover 3 is located extending over a trench 2 (FIGS. 6 and 7),the trench cover 3 covers the trench 2 as a substantially continuouscover. In particular there are no gaps or spaces through the trenchcover 2.

As illustrated in FIGS. 3 to 5, the anti-slip tile 4 comprises a bodyportion 5 having an upper surface 6 and a lower surface 7. When theanti-slip tile 4 is attached to the trench cover 3, the lower surface 7contacts the trench cover 3 (FIG. 2) and the upper surface 6 faces awayfrom the trench cover 3 (FIG. 2). The thickness of the body portion 5 isbetween 25 mm and 30 mm, in this case.

The body portion 5 comprises a main body part 14 a and two filler parts14 b. The main body part 14 a has two tapered main openings 11 atherethrough, and each filler part 14 b has a smaller diameter accessopening 11 b therethrough. As illustrated in FIG. 5, each main opening11 a tapers inwardly towards the lower surface 7 of the body portion 5.In use, the filler parts 14 b are located within the main openings 11 a,so that the filler parts 14 b substantially fill the main openings 11 a.Each filler part 14 b is of a tapered shape.

The anti-slip tile 4 comprises a plurality of cylindrical protrusions 8,9 protruding from the upper surface 6, and evenly spaced across theupper surface 6 (FIG. 3). The protrusions 8, 9 act to minimise thepossibility of a wheel of a vehicle slipping as the wheel passes overthe anti-slip tile 4 and over the trench cover 3. In this case, theprotrusions 8, 9 are integrally formed with the body portion 5.

The plurality of protrusions is divided into a set of first protrusions8 and a set of second protrusions 9. The first protrusions 8 protrude agreater distance from the upper surface 6, in this case approximately 4mm, than the second protrusions 9, which protrude approximately 2 mmfrom the upper surface 6 in this case.

As illustrated in FIG. 3, along the side edges of the anti-slip tile 4,the first protrusions 8 are arranged in a substantially “W”-shapedpattern relative to the second protrusions 9. In addition, the firstprotrusions 8 are arranged in a substantially cross-shaped patternrelative to the second protrusions 9 at the centre of the anti-slip tile4. In FIG. 3, the first protrusions 8 are marked with an X todifferentiate between the positions of the first protrusions 8 and thepositions of the second protrusions 9. However it will be appreciatedthat all of the protrusions 8, 9 have a cylindrical configuration, inthis case.

The anti-slip tile 4 is releasably attached to the trench cover 3 bymeans of a mechanical attachment arrangement, in this case by extendingtwo attachment members 10 through the corresponding access openings 11 bin the filler parts 14 b of the body portion 5 and into the trench cover3. In this case, each attachment member 10 is provided in the form of anail 15 having a head part 12 for engaging against the frusto-conicalshaped wedge filler part 14 b, which engages against the sides of themain opening 11 a, and a leg part 13 for extending through the accessopening 11 b in the filler part 14 b of the body portion 5 and into thetrench cover 3. The nail 15 may be driven into the trench cover 3 usingan impact gun, to fix the leg part 13 of the attachment member 10 inposition in the trench cover 3.

The head part 12 of the nail 15 is detachable from the leg part 13, forexample by grinding the head part 12, to facilitate release of theattachment of the anti-slip tile 4 to the trench cover 3.

In use, the anti-slip tile 4 is positioned with the lower surface 7 ofthe body portion 5 contacting the trench cover 3 at any desired positionon the trench cover 3. The nail 15 is driven through the access opening11 b in the filler part 14 b and into the trench cover 3, using animpact gun to fix the leg part 13 of the attachment member 10 inposition in the trench cover 3. In this fixed position, the head part 12engages against the filler part 14 b which engages against the sides ofthe main opening 11 a to maintain the anti-slip tile 4 releasablyattached to the trench cover 3.

The trench cover 3 with the anti-slip tile 4 attached thereto is thenpositioned with respect to a trench 2 to cover the trench 2, asillustrated in FIGS. 6 and 7.

If it is desired to release the attachment of the anti-slip tile 4 tothe trench cover 3, the head part 12 of the attachment member 10 may bedetached from the leg part 13, for example by grinding the head part 12.The anti-slip tile 4 can then be removed.

It will be appreciated that the anti-slip tile 4 may alternatively beattached to the trench cover 3 while the trench cover 3 is in positioncovering the trench 2.

Two or more of the anti-slip tiles 4 may be attached to the trench cover3 at any desired positions on the trench cover 3 to achieve the desiredlevel of anti-slip performance.

As an alternative to or in addition to the use of the attachment nail15, welding may be employed to attach the body portion 5 to the trenchcover 3.

To reduce the weight of the anti-slip tile 4, the anti-slip tile 4 mayinclude regions of reduced material, such as an opening through the tile4. For example by providing an opening through the anti-slip tile 4,between each set of four protrusions 8, 9, the overall weight of theanti-slip tile 4 may be reduced by up to 33%. Such an opening would alsolead to the benefit of improving the drainage of water, such asrainwater, from the upper surface of the tile 4. Improving drainagewould lead to improved anti-slip performance.

Other anti-slip means may be used in addition to or as an alternative tothe protrusions 8, 9. For example, points or grooves may be provided inthe upper surfaces 6 of the body portion 5.

Furthermore the height of the protrusions 8, 9 may be varied to achieveany desired anti-slip effect.

It will be appreciated that the anti-slip tile 4 and/or the trench cover3 could alternatively be manufactured using any other suitable metallicmaterial, or using a non-metallic material, or using a compositematerial. It will further be appreciated that the anti-slip tile 4and/or the trench cover 3 could alternatively be manufactured by anyother suitable manufacturing process, such as drawing, extruding,casting or injection moulding. By manufacturing the ant-slip tile 4and/or the trench cover 3 by means of an injection moulding process, theoverall weight of the anti-slip tile 4 and/or the trench cover 3 may bereduced.

In FIGS. 8 to 19, there is illustrated another anti-slip tile 20according to the invention, which is similar to the tile 4 of FIGS. 1 to7, and similar elements in FIGS. 8 to 19 are assigned the same referencenumerals.

In this case, the anti-slip tile 20 comprises a plurality of cylindricalprotrusions 21 protruding from the upper surface 6, and evenly spacedacross the upper surface 6. Each of the protrusions 21 is substantiallyidentical. In this case, each protrusion 21 is in the form of a dimplewith a square top.

The body portion 5 has a plurality of openings 22 extending through thebody portion 5, the openings 22 being spaced across the upper surface 6.The openings 22 assist in reducing the overall weight of the anti-sliptile 20.

It will be appreciated that the overall weight of the anti-slip tile ofthe invention may be reduced in a number of possible ways, for exampleby arranging one or more weight-reducing discontinuities across the bodyportion 5. The discontinuities could be in the form of openings 22through the body portion 5 (FIGS. 8 to 19), and/or in the form ofrecesses in the body portion 5, and/or in the form of thinned-down partsof the body portion 5, and/or in the form of a variation in the materialof the body portion 5 across the body portion 5.

The openings 22 also provide a means of draining water, such asrainwater, from the upper surface of the body portion 5. By drainingaway surface water, the overall anti-slip properties of the tile 20 arefurther improved.

As illustrated in FIG. 19, a rubber grommet 23 or washer may be providedbetween the base of the filler part 14 b and the trench cover 3. Thefiller part 14 b may be provided as a steel element, and a washer 24 maybe included between the head part 12 of the attachment member 10 and thetop surface of the filler part 14 b.

FIGS. 8 to 19 illustrate the countersunk nail insert stud/spacerembodiment of the invention, which comprises the countersunk spacer 14 bmanufactured from steel/aluminium/plastic/ductile iron, and theanti-skid tile 5 with countersunk location points 11 a which willreceive the matching countersunk spacer 14 b.

During assembly, the tiles 5 are laid out as desired. The countersunkspacer 14 b which has been machined with/without a through-hole 11 b orslotted hole provides for the insertion of a steel nail 15. Thecountersunk spacer 14 b is placed into the matching receiving points 11a located on the surface of the anti-skid tile 5. A steel nail 15 isfired from an impact gun, or an electric weld, can be used to fix thespacer 14 b to the surface of the steel road plate 3.

FIG. 20 to 29 illustrate another anti-slip tile 30 according to theinvention, which is similar to the tile 20 of FIGS. 8 to 19, and similarelements in FIGS. 20 to 29 are assigned the same reference numerals.

In this case, the two main openings 31 a in the main body part 14 a arelocated at opposite end edges of the main body part 14 a. As illustratedin FIG. 20, when viewed from above, the main openings 31 a have asubstantially “C”-shape or partially half-round shape. Similarly thefiller part 32 b has a substantially “C”-shape or partially half-roundshape, when viewed from above.

The access opening 33 through the filler part 32 b is substantiallyelongate, in this case, and the filler part 32 b tapers inwardly towardsthe lower surface 7 of the body portion 5.

FIGS. 20 to 29 illustrate the half-round anchor bracket embodiment ofthe invention, which comprises the half-round bracket 32 b manufacturedfrom 2 mm mild or stainless steel and formed with a punched, slottedhole 33, and the anti-skid tile 5 with indented edge profile to matchthe half-round bracket 32 b.

During assembly, a set of anti-skid tiles 5 is placed on the surface ofthe steel road plate 3 and spaced at intervals of 20-50 mm in order toevenly cover the surface of the steel sheet 3. A shaped, half roundbracket 32 b is inserted into the matching slot 31 a in the surface ofeach tile 5.

The shape of the bracket 32 b helps to create rigidity.

The bracket 32 b can be fixed to the surface of the steel road plate 3by means of a hardened nail fired from an impact gun. A slotted hole 33is provided which will also allow the formation of an electric arc weldin the centre of the bracket 32 b which will fix each bracket 32 b tothe surface of the plate 3 and as a consequence, secure the tile 30.

A tile 30 will normally be fixed by a minimum of 2 brackets.

In another method it will be possible to fix a tile 30 with only onebracket located in the centre of the tile 30. This method would requirea bracket which has a shape other than circular such as a square shape,so that the tile 30 cannot rotate around its centre.

Referring to FIGS. 30 to 39, there is illustrated a further anti-sliptile 40 according to the invention, which is similar to the tile 30 ofFIGS. 20 to 29, and similar elements in FIGS. 30 to 39 are assigned thesame reference numerals.

In this case the attachment member 41 comprises a first wing 42, asecond wing 43 and a raised lip 44 bridging the two wings 42, 43 (FIGS.36 to 38). The attachment member 41 is suitable for clamping the bodyportion 5 to the trench cover 3.

The second wing 43 is insertable through an access opening 45 in thebody portion 5, to locate the second wing 43 between the lower surface 7of the body portion 5 and the upper surface of the trench cover 3. Arecess 46 is provided in the lower surface 7 of the body portion 5 toaccommodate the second wing 43, while enabling the body portion 5 to lieflush on the trench cover 3.

The body portion 5 has a fixing opening 47 at an edge of the bodyportion 5, and the first wing 42 may be located in the fixing opening 47for fixing of the first wing 42 to the trench cover 3. A fixing member,such as the nail 15, may be driven through the first wing 42 and intothe trench cover 3 to fix the attachment member 41 to the trench cover3. An impact gun may be used to drive the fixing member 15 through thefirst wing 42. In this configuration, the lip 44 extends over thebridging finger 48 between the access opening 45 and the fixing opening47, and the body portion 5 is thereby clamped to the trench cover 3.

FIGS. 30 to 39 illustrate the flat anchor bracket embodiment of theinvention, which comprises a flat/stepped anchor bracket 41 manufacturedfrom mild or stainless steel and formed with a raised portion 44 in theupper, central section of the rectangular bracket 41 which is parallelto the lower sections 42, 43 and an anti-skid tile 5 with a rectangular,slotted indentation 47 on two sides/ends, which will receive the anchorbracket 41.

During assembly, the tiles 5 are laid out as desired. Thestepped/rectangular bracket 41 is inserted through the matching 30 mmslot 45 which has been cast into the tiles 5 at each end. On theunderside of the anti-skid tile 5, a counter-sunk position 46 has beencast in order to receive the rectangular bracket 45. This will allow theanti-skid tile 5 to remain flush with the surface of the steel roadplate 3. The rectangular bracket 42 can then be fixed to the surface ofthe steel road plate 3 by means of a hardened nail 15 fired from animpact gun. It will also be possible to fix the bracket 41 by means ofan electric arc weld.

FIGS. 40 to 44 illustrate another anti-slip tile 50 according to theinvention, which is similar to the tile 40 of FIGS. 30 to 39, andsimilar elements in FIGS. 40 to 44 are assigned the same referencenumerals.

In this case the attachment member 51 is elongate, and is extendableover two or more body portions 5 to clamp the body portions 5 to thetrench cover 3 using a single attachment member 51, as illustrated inFIG. 43.

The attachment member 51 comprises a plurality of wings 52 separated bya plurality of raised lips 53. Each wing 52 is locatable in acorresponding fixing opening 54 at a edge of the body portion 5, andeach lip 53 is extendable over the body portion 5 between adjacentfixing openings 54. By fixing each wing 52 to the trench cover 3, forexample by driving fixing members 15 through each wing 52 and into thetrench cover 3, the plurality of body portions 5 will be clamped to thetrench cover 3.

FIGS. 40 to 44 illustrate the strip anchor method embodiment of theinvention. It can be seen that it is possible to press the half-roundanchor bracket 51 from a continuous strip of metal, referred to as a“strip anchor method”. In this method, the user will place a set or rowof anti-skid tiles 5 on the surface of the steel road plate 3. It isthen possible to place an anchoring strip 51 which, in one continuouslength, will anchor a number of plates 3 at one time. The anchor strip51 is fitted with shaped countersunk portions 52 which will matchcutaway notches 54 in the anti-skid tile 5. The anchor strip is providedwith a number of slotted holes 55 through which a steel nail can befired by means of an impact gun or through which an electric arc weldcan be made.

Although the anti-slip tile of the invention has been described inrelation to attachment to a trench cover, it will be appreciated thatthe anti-slip tile is also applicable for attachment to a variety ofother surfaces. For example the anti-slip tile could be attached to afloor of a building, such as a factory.

In another embodiment of the invention, a trench cover could bemanufactured with a series of recesses on an upper surface of the trenchcover. A corresponding series of stud elements could be fitted into therecesses so as to partially protrude from the upper surface. Thepartially protruding stud elements will therefore act to minimise thepossibility of a wheel of a vehicle slipping as the wheel passes overthe trench cover and the studs.

Referring to FIGS. 45 to 79, there is illustrated a trench cover 101according to the invention. The trench cover 101 is similar to thetrench covers described in International patent applications publishedunder numbers WO 02/084033 and WO 01/21898, the relevant contents ofwhich are incorporated herein by reference. The trench cover 101 may beused to cover a trench in the ground and a number of the trench covers101 may be interlinked to follow the contour of the ground in which thetrench is dug.

The cover 101 comprises a cover member 102 for extending over a trench,especially in a roadway. The cover member 102 comprises a pair ofsupporting portions 110, 111 bridged by a central trench coveringportion 112. The cover member 102 is of a generally convex shape intransverse cross section (FIG. 49), the side portions 110, 111 reducingin cross section towards opposite marginal edges 114, 115 of the covermember 102 to define a slight ramp to facilitate vehicle wheels and thelike passing thereover. The exposed upper surface of the cover member102 has anti-slip formations which in this case are defined byprotrusions 116.

The protrusions 116 protrude upwardly from the upper surface of thecover member 102, and are integrally formed with the cover member 102.The protrusions 116 are evenly spaced across the upper surface of thecover member 102, with each of the protrusions 116 being substantiallyidentical. In this case, each protrusion 116 has a lower portion with asubstantially round-shaped cross-section and an upper portion with asubstantially square-shaped cross-section (FIG. 54). The lower portionis located closer to the upper surface of the cover member 102 than theupper portion.

In use, as traffic/pedestrians pass over the cover member 102, theprotrusions 116 act to minimise the possibility of thetraffic/pedestrians slipping.

FIG. 54 illustrates the dimpled upper surface of the cover member 102which is covered with a dimpled/coarse surface which creates ananti-skid surface for vehicles and pedestrians.

In one application, this surface is as shown whereby a raised/rounddimple will have a square top which provides for a given skid resistancevalue (SRV) according to traffic regulation guidelines.

Anchor holes 119 are provided in the supporting portions 110, 111 tofacilitate anchoring to the ground, if desired. A central recessed area120 is provided for attachment of a reflector strip or the like. Tofacilitate erection of a post for a warning flag, sign or the like thecover member 102 has a mounting hole 121. Another recess may be providedto receive a coding means such as an identity tag or transponder unit touniquely identify the cover 101 for tracing and the like. The supportingportions 110, 111 also have slots therein defining carrying handles 109for the cover 101.

The cover member 102 has a pair of transverse sides 125, 126 extendingtransversely between opposite marginal edges 114, 115. Confinement meansin the form of trench engaging elements 127, 128 confine the cover 101with respect to the opening of the trench. Referring in particular toFIG. 46, it will be noted that the two trench engaging elements 127, 128depend from the central trench covering portion 112 of the cover member102, and are oppositely directed so that, in use, they can engageopposite side walls of the trench.

The trench engaging elements 127, 128 are linearly movable relative tothe cover member 102 to facilitate adjustment to a desired width oftrench. In particular, the trench engaging elements 127, 128 comprisearms 1000, 1010 with elongate slots 1020, 1030 respectively foradjustment relative to the cover member 102.

Means to lock the trench engaging elements 127, 128 in a desiredposition relative to the cover member 102 are provided in the form offixing pins 1040, 1050 respectively. The pins 1040, 1050 are extendablethrough aligned openings in the arms 1000, 1010 and the cover member 102to lock the trench engaging elements 127, 128 in a particular position.In this case, the fixing pins 1040, 1050 are provided in the form ofthreaded bolts coupled to corresponding threaded nuts.

As illustrated particularly in FIGS. 55 and 56, each slot 1020, 1030 hasa range of discrete enlarged openings 1100. Each trench engaging element127, 128 is movable between a number of discrete locations as defined bythe enlarged openings 1100. The cover has two protrusions 1500, 1510 onthe underside thereof for engagement in the slots 1020, 1030 andopenings 1100. The protrusions 1500, 1510 each have an enlarged portion1520, 1530 for engagement in one of the openings 1100 respectively inthe trench engaging elements 127, 128. Each protrusion 1500, 1510 alsocomprises an elongate extension 1540, 1550 for engagement in the slots1020, 1030. In this case there are five discrete enlarged openings 1100in each of the trench engaging elements 127, 128. When the trenchengaging elements 127, 128 are moved inwardly to their fullest extent,this corresponds to a given trench width, of say 300 mm. When the trenchengaging elements 127, 128 are moved outwardly to the fullest extent,this corresponds to a maximum trench width, of say 500 mm. Adjustment ofthe trench engaging element 127, 128 from one hole to the adjacent holerepresents an extension of the trench engaging element 127, 128 by afixed distance, of say 25 mm. To move the trench engaging element 127,128 from one hole to the next, the fixing bolts 1040, 1050 are releasedand the trench engaging element 127, 128 is lifted off the protrusion1500, 1510 and moved linearly until the protrusion 1520, 1530 is in linewith the desired hole 1100. The trench engaging element 127, 128 is thenengaged with the protrusion 1500, 1510 and the fixing bolts 1040, 1050tightened to fix the trench engaging elements 127, 128 to the covermember 102 in position corresponding to the desired width. The trenchengaging element 127, 128 may have an imprint therein adjacent to eachhole 1100 to indicate the corresponding trench width to a user.

Thus, to adjust the distance between the trench engaging elements 127,128 to correspond to the width of a trench to be covered, one or bothfixing pins 1040, 1050 are released, the arms 1000, 1010 linearlyadjusted and the fixing pins 1040, 1050 are then re-locked. The trenchengaging elements 127, 128 are adjustable to accommodate a range oftrench widths, typically from 300 to 500 mm. The trench engagingelements 127, 128 are preferably incrementally adjustable in incrementsof typically 25 mm.

Each arm 1000, 1010 has a depending handle formation 2500 at theopposite end to the fixing pins 1040, 1050 (FIG. 46). The handles 2500enable a user to easily grip and move the trench engaging elements 127,128.

Protective side walls 2510, 2520, which are fixed relative to the covermember 102, also depend from the central trench covering portion 112 ofthe cover member 102 on both sides of the arms 1000, 1010. The sidewalls 2510, 2520 guide and protect the movable arms 1000, 1010.

Interlink means are also provided in the form of a first male interlinkmeans and a second female interlink means, the interlink means ofadjacent like covers 101 being interengagable on assembly of the covers101.

In this case, the male interlink means comprises a head part 135projecting from the transverse side 126 of the cover member 102. Thehead part 135 has an area of reduced cross section defining a neck 136and is located centrally of the transverse side 126.

The female interlink means comprises a downwardly opening slot 140 atthe transverse side 125. The slot 140 is defined in the underside of thecover member 102 by downwardly extending walls and portion of thetransverse wall. The width of the slot 140 is oversize with respect tothe width of the head part 135 of the male interlink to permit limitedrelative movement between adjacent covers 101 on assembly so that thecovers 101 can follow the contour of the ground. Similarly, the lengthof the head part 135 is less than the length of the recess 140. It willbe noted that the upper ends of the head part 135 are tapered tofacilitate assembly of the head part 135 into the recess 140.

The interlink means in this case also comprises a pair of end wings 150,151 which extend from the transverse side 125. The end wings 150, 151are located on either side of the recess 140 and extend generally fromthe supporting portions 110, 111 of the cover member 102 respectively.On assembly, the end wings 150, 151 are received underneath an adjacentcover 101. In this case, the end wings 150, 151 are received in recessedareas 152, 153 respectively flanking the head part 135.

The end wings 150, 151 engaging underneath an adjacent cover 101, incombination with the inter-engagement of the head part 135 in the slot140 secures adjacent covers 101 together in such a way as to facilitaterelative movement between adjacent covers 101 to follow the contour of atrench.

Because both of the trench engaging elements 127, 128 may be movedrelative to the cover member 102, this enables the cover 101 to beadjusted so that the cover 101 is confined with respect to the trenchregardless of the trench width, while also enabling the cover 101 to bepositioned centrally over the trench with substantially equal amounts ofthe supporting portions 110, 111 on each side of the trench. The widthadjustment may be made at a depot or on site so that the cover 101 isconfigured for a particular trench size.

The trench cover 101 further comprises two separate mats 300, 301 oneach supporting portion 110, 111. The larger “L”-shaped mat 300 isprovided in the region of the corner of the marginal edge 114, 115 andthe transverse side 126, and extends partially along the transverse side126 towards the head part 135 (FIG. 46). The smaller mat 301 is providedin the region of the corner of the marginal edge 114, 115 and thetransverse side 125 (FIG. 46).

Each of the mats 300, 301 is mounted to the lower surface of thesupporting portion 110, 111. In particular the larger mat 300 has threemale protrusions 302 which are engagable in three corresponding femalerecesses 303 in the lower surface of the supporting portion 110, 111 tomount the mat 300 to the lower surface of the supporting portion 110,111. Similarly the smaller mat 301 has one male protrusion 304 which isengagable in a corresponding female recess 305 in the lower surface ofthe supporting portion 110, 111 to mount the mat 300 to the lowersurface of the supporting portion 110, 111.

In use, the mats 300, 301 are located between part of the supportingportions 110, 111 and the ground on each side of the trench. The mats300, 301 are of a resilient material, in this case rubber. Thus the mats300, 301 act as cushioning members to cushion the cover member 102relative to the ground on both sides of the trench. In particular themats 300, 301 minimise vibration of the cover member 102 and minimiseany noise generated as traffic/pedestrians pass over the cover member102. The mats 300, 301 may become at least partially compressed astraffic/pedestrians pass over the cover member 102. The resilient natureof the mats 300, 301 enable the mats 300, 301 to accommodatefluctuations in the surface of the ground either side of the trench.

The larger mat 300 has a stepped configuration, as illustrated in FIGS.72 and 73. In particular the larger mat 300 has a relatively thickportion 350 located in the region of the corner of the “L”, and tworelatively thin portions 351, 352 either side of the thick portion 350.As illustrated in FIG. 46, the thick portions 350 protrude downwardlyfrom the lower surface of the cover member 102, so that in use the thickportions 350 support the cover member 102 suspended by a small distanceoff the ground. Upon passage of traffic over the trench cover 101, theresilient thick portions 350 at least partially compress until the covermember 102 contacts the ground. In this manner the thick portions 350accommodate any unevenness in the surface of the ground.

The thin portions 351 contact the end wings 150, 151 of an adjacenttrench cover 101, when two adjacent trench covers 101 are interlinked.When two trench covers are interlinked, the thin portions 351 arelocated between the end wings 150, 151 of one trench cover 101 and therecessed areas 152, 153 of the adjacent trench cover 101. The resilientthin portions 351 therefore act as insulators to minimise vibration andnoise as traffic passes over the interlinked trench covers 101.

It will be appreciated that the cushioning means may be provided in avariety of possible configurations and is not limited to the particularshape of the mats as described with reference to FIGS. 45 to 79.

Furthermore it will be appreciated that a variety of possible means maybe employed to mount the mats to the cover member.

Advantageously the mats are replaceable for repair/replacement, asrequired.

In use, the cover 101 is located over a trench in the ground with thesupporting portions 110, 111 on either side of the trench and thecentral portion 112 bridging the trench.

Like covers 101 are then interengaged, by locating the head part 135 ofone cover 101 into the slot 140 of an adjacent cover 101. The end wings150, 151 of one cover 101 are also received in the recessed areas 152,153 of an adjacent cover 101 during interlinking.

In this manner, a plurality of covers 101 may be interlinked to form acover assembly over a trench of any length or configuration.

Because the trench cover 101 of the invention permits a degree ofrelative movement between adjacent covers 101 of an assembly, it ispossible for the covers 101 to follow a curvilinear course, for exampleto cover a curved trench.

On assembly, end covers 101 may be anchored to the ground and because ofthe inter-engagement on both transverse sides 125, 126, none of thecovers 101 in the assembly can be removed by an unauthorised person.This prevents theft and also enhances the safety aspects of theassembly. In addition, the end wings 150, 151 have the importantadvantage that they at least partially occlude any gap between adjacentcovers 101 on assembly. This is also an important safety feature asthere is no gap on which to snag a bicycle wheel or the like.

At least one transverse side, in this case the transverse side 125 isshaped to facilitate limited relative movement between side edges 125,126 of adjacent covers 101. In this case the transverse side 125 is ofgenerally convex curvilinear shape.

The covers 101 are readily assembled as described above to form a rigidtemporary trench cover that can be easily disassembled. Importantly,controlled relative movement is allowed so that the cover 101 followsthe contour of the ground, preferably in both the vertical andhorizontal planes. This ensures a particularly safe and even temporarysurface over a trench opening.

The covers 101 may include a code tracking means such as a transponderwhich may be housed within the cover 101 to allow the location of thecover 101 to be determined from a remote location. In this way the hireand use of the covers 101 can be controlled.

The invention provides a simple yet extremely effective temporary cover101 for a range of trench widths. Adjacent covers 101 are readilyinterconnected as described above. The fittings allow the cover 101 toreadily follow both the contour of the ground in which the trench is dugand also the path of the trench.

The trench cover 101 may be anchored into position. Usually, the cover101 will be anchored at either end by, for example, an anchor bolt whichmay subsequently be temporarily covered. The cover 101 may also beanchored to the trench at any suitable point, for example at 5 m length.The anchoring may be achieved by a releasable hook linkage between thecover 101 and a trench strut.

The trench cover assembly of the invention is easily handled and cantherefore be used to allow traffic access and avoid the necessity fortemporary backfilling. Thus, the labour force can be concentrated on thetrench digging operation, which is thereby optimised.

Although specific configurations for the anti-slip protrusions have beendescribed above with reference to FIGS. 1 to 79, it will be appreciatedthat the anti-slip means could be provided in a variety of possibleconfigurations within the scope of the invention. For example theanti-slip means could be provided in the form of a stepped protrusion, arecess or opening may be provided extending into the centre of aprotrusion, adjacent protrusions may or may not have differing heights.

The invention is not limited to the embodiments hereinbefore described,with reference to the accompanying drawings, which may be varied inconstruction and detail.

1. An anti-slip element for use with a separately formed trench cover,the anti-slip element comprising: a body portion, the body portion beingattachable to a separately formed trench cover; and means to minimisethe possibility of another element slipping upon passage of the otherelement over the body portion.
 2. An element as claimed in claim 1wherein the body portion is releasably attachable to a trench cover. 3.An element as claimed in claim 2 wherein the body portion is attachableto a trench cover by means of a mechanical attachment. 4-6. (canceled)7. An element as claimed in claim 3 wherein the mechanical attachmentincludes an attachment member configured to be driven into a trenchcover by an impact gun. 8-21. (canceled)
 22. An element as claimed inclaim 7 wherein the element comprises an attachment member for clampingthe body portion to a trench cover.
 23. An element as claimed in claim22 wherein the attachment member comprises a lip for extending over atleast part of the body portion to clamp the body portion to a trenchcover.
 24. An element as claimed in claim 22 wherein the attachmentmember comprises a first wing configured to be fixed to a trench cover.25. An element as claimed in claim 24 wherein the element comprises afixing member drivable through the first wing to fix the first wing to atrench cover.
 26. An element as claimed in claim 25 wherein the fixingmember is configured to be driven through the first wing by an impactgun.
 27. An element as claimed in claim 24 wherein the body portioncomprises a fixing opening, the first wing being locatable in the fixingopening.
 28. An element as claimed in claim 24 wherein the attachmentmember comprises a second wing configured to be located between the bodyportion and a trench cover.
 29. An element as claimed in claim 28wherein the body portion comprises a recess for accommodating the secondwing.
 30. An element as claimed in claim 22 wherein a single attachmentmember is configured to clamp the body portions of two or more elementsto a trench cover.
 31. An element as claimed in claim 1 wherein the bodyportion is attachable to a trench cover by means of welding.
 32. Anelement as claimed in claim 1 wherein the slip minimisation means isintegrally formed with the body portion.
 33. An element as claimed inclaim 1 wherein the body portion comprises an upper surface for facingaway from a trench cover when the body portion is attached to the trenchcover, and the slip minimisation means comprises one or more protrusionsprotruding from the upper surface.
 34. An element as claimed in claim 33wherein the slip minimisation means comprises a plurality of protrusionsevenly spaced across the upper surface.
 35. An element as claimed inclaim 34 wherein each of the protrusions is substantially identical.36-39. (canceled)
 40. An element as claimed in claim 1 wherein the bodyportion comprises one or more weight-reducing discontinuities.
 41. Anelement as claimed in claim 40 wherein the one or more discontinuitiescomprise one or more openings extending through the body portion.
 42. Anelement as claimed in claim 1 wherein the body portion comprisesdrainage means.
 43. An element as claimed in claim 42 wherein thedrainage means comprises an opening extending through the body portion.44-45. (canceled)
 46. An assembly for covering a trench, the assemblycomprising: a separately formed trench cover; an anti-slip elementincluding: a body portion, the body portion being attachable to theseparately formed trench cover; and means to minimise the possibility ofanother element slipping upon passage of the other element over the bodyportion. 47-53. (canceled)
 54. An assembly as claimed in claim 46wherein the trench cover comprises an upper surface, and the uppersurface is substantially smooth. 55-56. (canceled)
 57. A method forcovering a trench, the method comprising the steps of: providing ananti-slip element; providing a separately formed trench cover; attachingthe anti-slip element to the trench cover; and positioning the trenchcover with respect to the trench to cover the trench.
 58. A method asclaimed in claim 57 further comprising the step of attaching theanti-slip element to the trench cover before covering the trench.
 59. Amethod as claimed in claim 57 further comprising the step of attachingthe anti-slip element to the trench cover while the trench cover is inposition covering the trench. 60-65. (canceled)
 66. A method as claimedin claim 57 wherein the step of attaching the anti-slip element to thetrench cover further comprises the step of releasably attaching theanti-slip element to the trench cover. 67-95. (canceled)